CN111817366B - Medium-voltage DC input dual-output three-level phase-shifted full-bridge charging device and online charging control method - Google Patents

Abstract

The invention discloses a medium-voltage direct current input dual-output three-level phase-shifted full-bridge charging device, comprising an input circuit, a three-level inverter component, a three-winding intermediate frequency transformer, a rectifier component and an output circuit. The electricity is sent to the three-level inverter component, and the three-level inverter component converts the direct current into intermediate frequency alternating current and transmits it to the three-winding intermediate frequency transformer. The two intermediate frequency alternating currents are converted into two direct currents and sent to the output circuit, and the output circuit filters the two direct currents and charges the two supercapacitors. It adopts an isolated three-level topology structure based on a three-winding intermediate frequency transformer, which simultaneously meets the multiple requirements of medium voltage DC input, dual output, input and output electrical isolation, simple structure, high power density and high reliability, and solves the problem of electromagnetic emission in the process. Fast online charging of supercapacitors.

Description

Medium-voltage DC input dual-output three-level phase-shift full-bridge charging device and online charging control method

technical field

The invention belongs to the technical field of power electronic energy conversion devices, and in particular relates to a medium-voltage DC input dual-output three-level phase-shifted full-bridge charging device and an online charging control method.

Background technique

With the continuous advancement of technology in recent years, electromagnetic emission has gradually moved from a new concept of emission to engineering practice, and it has huge potential advantages and broad application prospects in both military and civilian fields. The electromagnetic launch process requires enormous instantaneous power, and the capacity of the power grid cannot meet the demand. Therefore, an energy storage system must be configured in the electromagnetic launch device to reduce the instantaneous power demand of the power grid for continuous high-power transmission.

Supercapacitor energy storage has the advantages of high power density, short energy storage period, long cycle life, and wide operating temperature range. It is very suitable for electromagnetic emission and other applications that require high power density and rapid energy storage/release. When using supercapacitors for energy storage, a charging device needs to be configured in the energy storage system. The main function of the charging device is to charge the supercapacitor and supplement the electric energy consumed during the launch process. The current converter topologies suitable for supercapacitor charging are divided into two categories: non-isolation and isolation. The non-isolation topology has low power level and low safety; the two-level structure in the isolation topology has a low voltage level, and the series-parallel based two-level structure The combined and modular multi-level structure is too complicated. Electromagnetic emission usually uses relatively small power to store energy before emission, and the charging device stops during the emission process. However, in the application of fast and continuous emission, the charging device needs to charge the super capacitor online during the emission process to quickly supplement the consumption during the emission process. power to meet the requirements of the next launch.

SUMMARY OF THE INVENTION

The purpose of the present invention is to aim at the defects of the prior art, to provide a medium-voltage DC input dual-output three-level phase-shifted full-bridge charging device and online charging that simultaneously satisfy the requirements of medium-voltage DC input, single-input dual-output, and input-output electrical isolation. Control Method.

In order to achieve the above purpose, the medium-voltage DC input dual-output three-level phase-shifted full-bridge charging device designed by the present invention includes an input loop, a three-level inverter assembly, a three-winding intermediate frequency transformer, a rectifier assembly and an output loop. The loop takes electricity from the medium voltage DC grid and transmits it to the three-level inverter component. The three-level inverter component converts the direct current into intermediate frequency alternating current and sends it to the three-winding intermediate frequency transformer. The three-winding intermediate frequency transformer reduces the intermediate frequency alternating current and divides it into The two paths are sent to the rectifier assembly, which converts the two paths of intermediate frequency alternating current into two paths of direct current and sends them to the output circuit, which filters the two paths of direct current and charges the two paths of super capacitors.

Further, a control system is also included, and the control system performs bidirectional communication with the input loop, the three-level inverter component, the three-winding intermediate frequency transformer, the rectifier component, and the output loop, respectively.

Further, a closed circulation cooling water circuit is also included, which is used to take away the heat generated during the operation of the input circuit, the three-level inverter component, the three-winding intermediate frequency transformer, the rectifier component and the output circuit.

Further, the input loop 1 includes an input fuse F1, an input fuse F2, an input contactor K1, an input smoothing reactor L1, an input smoothing reactor L2, an input diode D1, a supporting capacitor C1, a supporting capacitor C2, The voltage equalizing resistor Rj1 and the voltage equalizing resistor Rj2, and the charging and discharging component composed of the charging switch Kc1, the charging resistor Rc1, the charging reactor Lc1, the charging switch Kc2, the charging resistor Rc2, the charging reactor Lc2, the discharging switch Kd, and the discharging resistor Rd ; And the input contactor K1 is a mechanical holding type, and the contacts are not opened when the control is powered off.

Further, the three-level inverter components include IGBT-T1, IGBT-T2, IGBT-T3, IGBT-T4, IGBT-T5, IGBT-T6, IGBT-T7, IGBT-T8, clamp diode Dc1, clamp diode Bit diode Dc2, clamping diode Dc3, clamping diode Dc4, inner tube protection resistor Rj3, inner tube protection resistor Rj4, absorption capacitor Cs1, absorption capacitor Cs2.

Further, the three-winding intermediate frequency transformer includes one primary winding and two secondary windings; the rectifier assembly includes a rectifier diode Dr1, a rectifier diode Dr2, a rectifier diode Dr3, a rectifier diode Dr4, and a resistance-capacitance absorption circuit.

Further, the output loop includes an output filter reactor L3, an output filter reactor L4, an output diode D2, an output fuse F3, and an output fuse F4.

Further, the control system includes a top-level controller and a bottom-level controller, and the top-level controller and the bottom-level controller are connected by a CAN bus and a hard wire; the top-level controller is used to provide a human-computer interaction control interface, and receives the upper-level system control. command, send control commands to the charging and discharging components and the input contactor K1, and send control commands to the underlying controller; the underlying controller is used to collect voltage and current data to complete closed-loop operations according to the received control commands, and realize the three-level inverter. On-off control of the IGBTs in the assembly.

Further, the closed circulation cooling water circuit includes a main water inlet pipe, a main drain pipe, an input diode D1 branch, a three-level inverter component branch, a three-level inverter component water cooling plate, a three-winding intermediate frequency transformer branch, Rectifier component water cooling plate, rectifier component branch, output filter reactor branch, output diode D2 branch, output diode D2 water cooling plate and water-air heat exchanger branch, input diode D1 branch water inlet, three-level inverter The water inlet of the transformer branch, the water inlet of the rectifier branch, the water inlet of the output filter reactor branch, the water inlet of the output diode D2 branch, the water inlet of the three-winding intermediate frequency transformer branch and the water-air heat exchanger The water inlet of the branch is connected with the main water inlet pipe, the water outlet of the input diode D1 branch, the water outlet of the three-level inverter component branch, the water outlet of the rectifier component branch, and the water outlet of the output filter reactor branch , The water outlet of the output diode D2 branch, the water outlet of the three-winding intermediate frequency transformer branch and the water outlet of the water-air heat exchanger branch are all connected to the main drain pipe, and the water-cooling plate of the three-level inverter component is connected to the three-level inverter. The variable component branch is connected, the rectifier component water cooling plate is connected with the rectifier component branch, and the output diode D2 water cooling plate is connected with the output diode D2 branch.

Also provided is an online charging control method for a medium-voltage DC input dual-output three-level phase-shifted full-bridge charging device as described above, using the maximum value of the two output currents as the feedback current to participate in the PI operation to obtain the left and right bridge arm shift of the three-level inverter assembly. Phase angle, the charging device maintains constant current output by adjusting the phase shift angle, and uses the maximum value of the two output voltages to participate in the hysteresis judgment to prevent the supercapacitor from overvoltage; when the supercapacitor voltage is less than the threshold 1, the PI regulator is enabled, The charging device outputs two constant currents to charge the supercapacitor; when the supercapacitor voltage is greater than or equal to the threshold 2, the PI regulator is disabled, and the charging device stops charging, where the threshold 2 is greater than the threshold 1.

Compared with the prior art, the present invention has the following advantages:

1) It adopts an isolated three-level topology structure based on a three-winding intermediate frequency transformer, which meets the multiple requirements of medium voltage DC input, dual output, input and output electrical isolation, simple structure, high power density and high reliability, and solves the problem of electromagnetic emission. The problem of fast online charging of super capacitors in the process;

2) Since the DC output is filtered by a reactor, the charging current ripple is small, which reduces the temperature fluctuation of the super capacitor and improves the life of the super capacitor;

3) The input loop adopts contactor and fuse, which provides a new idea of short-circuit protection, and at the same time improves the flexibility and reliability of parallel operation on the input side.

Description of drawings

FIG. 1 is a schematic diagram of the principle of the present invention.

FIG. 2 is a circuit schematic diagram of the present invention.

FIG. 3 is a structural diagram of a closed circulation cooling water circuit of the present invention.

FIG. 4 is a schematic diagram of the control system of the present invention.

FIG. 5 is a control block diagram of the online charging control method of the present invention.

Detailed ways

The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted here that the descriptions of these embodiments are used to help the understanding of the present invention, but do not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as there is no conflict with each other.

As shown in Figure 1, the medium-voltage DC input dual-output three-level phase-shifted full-bridge charging device includes an input circuit 1, a three-level inverter component 2, a three-winding intermediate frequency transformer 3, a rectifier component 4, an output circuit 5, a closed loop The relationship between the cooling water circuit 6 and the control system 7 is mainly divided into energy flow, information flow and cooling water flow. The energy flow direction is: each time the super capacitor is charged, the input circuit 1 takes electricity from the medium voltage DC grid and transmits it to the third. The level inverter component 2, the three-level inverter component 2 converts the direct current into intermediate frequency alternating current and transmits it to the three-winding intermediate frequency transformer 3, and the three-winding intermediate frequency transformer 3 reduces the intermediate frequency alternating current and then transmits it to the rectifier component 4 in two ways. 4. Convert the two channels of intermediate frequency alternating current into two channels of direct current and send them to the output circuit 5. The output circuit 5 filters the two channels of direct current and charges the two channels of super capacitors; The state data of component 2, three-winding intermediate frequency transformer 3, rectifier component 4 and output circuit 5 send different control commands to input circuit 1 and three-level inverter component 2, and each part of the control energy flow is executed according to the predetermined program, and The health status of each part of the energy flow and its own can be diagnosed in real time; the cooling water flow is: after the deionized water flows into the main water inlet pipe, it is divided into multiple branches and flows to each part of the energy flow, and then flows out after the main water outlet pipe converges. The functions of each part are as follows:

Input circuit 1 is used to take power from the medium voltage DC grid, filtered by the support capacitor, and then sent to the three-level inverter component 2; the input contactor is used to facilitate parallel operation of multiple inputs; the fuse and input diode are used to achieve short-circuit protection. The three-level inverter component 2 is used to convert the input DC power into an intermediate frequency AC power and output it to a three-winding intermediate frequency transformer. The three-winding intermediate frequency transformer 3 is used to step down the intermediate frequency alternating current and then transmit it to the rectifier assembly 4 in two ways. The rectifier assembly 4 is used to convert the two-way intermediate frequency alternating current into two-way direct current and send it to the output circuit 5 . The output loop 5 is used to charge the two supercapacitors after the two-way direct current is filtered by the output reactor. The closed circulation cooling water circuit 6 is used to take away the heat generated during the operation of the input circuit 1 , the three-level inverter component 2 , the three-winding intermediate frequency transformer 3 , the rectifier component 4 and the output circuit 5 .

The control system 7 is used to collect the status data of the input loop 1, the three-level inverter assembly 2, the three-winding intermediate frequency transformer 3, the rectifier assembly 4 and the output loop 5, and send different signals to the input loop 1 and the three-level inverter assembly 2. The control instruction is controlled to control the charging device to execute according to a predetermined program to charge the super capacitor. The control system 7 provides the man-machine interface between the operator and the system device, and at the same time receives the control instructions of the upper-level system, and uploads the status data to the upper-level system.

As shown in Figure 2, the input circuit 1 includes an input fuse F1, an input fuse F2, an input contactor K1, an input smoothing reactor L1, an input smoothing reactor L2, an input diode D1, a supporting capacitor C1, and a supporting capacitor C2 , equalizing resistor Rj1 and equalizing resistor Rj2, and charging and discharging composed of charging switch Kc1, charging resistor Rc1, charging reactor Lc1, charging switch Kc2, charging resistor Rc2, charging reactor Lc2, discharging switch Kd, discharging resistor Rd components. The three-level inverter component 2 includes IGBT-T1, IGBT-T2, IGBT-T3, IGBT-T4, IGBT-T5, IGBT-T6, IGBT-T7, IGBT-T8, clamping diode Dc1, clamping diode Dc2, Clamping diode Dc3, clamping diode Dc4, inner tube protection resistor Rj3, inner tube protection resistor Rj4, absorption capacitor Cs1, absorption capacitor Cs2. The three-winding intermediate frequency transformer 3 includes one primary winding and two secondary windings. The rectifier assembly 4 includes a rectifier diode Dr1, a rectifier diode Dr2, a rectifier diode Dr3, a rectifier diode Dr4, and a resistance-capacitance absorption circuit. The output loop 5 includes an output filter reactor L3, an output filter reactor L4, an output diode D2, an output fuse F3, and an output fuse F4.

As shown in FIG. 3, the closed circulation cooling water circuit 6 includes a main water inlet pipe 8, a main drain pipe 9, an input diode D1 branch 10, a three-level inverter assembly branch 19, a three-level inverter assembly water cooling plate 15, Three-winding intermediate frequency transformer branch 16 , rectifier assembly water cooling plate 14 , rectifier assembly branch 18 , output filter reactor branch 13 , output diode D2 branch 17 , output diode D2 water cooling plate 12 and water-air heat exchanger branch 13 , the water inlet of the input diode D1 branch 10, the water inlet of the three-level inverter component branch 19, the water inlet of the rectifier component branch 18, the water inlet of the output filter reactor branch 13, and the output diode D2 branch 17 The water inlet of the three-winding intermediate frequency transformer branch 16 and the water inlet of the water-air heat exchanger branch 13 are all connected to the main water inlet pipe 8, and the water outlet of the input diode D1 branch 10, the three-level inverter component The water outlet of the branch 19, the water outlet of the rectifier assembly branch 18, the water outlet of the output filter reactor branch 13, the water outlet of the output diode D2 branch 17, the water outlet of the three-winding intermediate frequency transformer branch 16 and the water wind The water outlet of the heat exchanger branch 13 is connected to the main drain pipe 9, the three-level inverter assembly water cooling plate 15 is connected to the three-level inverter assembly branch 19, and the rectifier assembly water cooling plate 14 is connected to the rectifier assembly branch 18. , the water cooling plate 12 of the output diode D2 is connected to the branch 17 of the output diode D2.

As shown in FIG. 4 , the control system 7 includes a top-level controller and a bottom-level controller, and the top-level controller and the bottom-level controller are connected by a CAN bus and a hard wire. The top-level controller adopts the hardware solution of PLC plus HMI, and the bottom-level controller adopts the hardware solution of DSP plus FPGA.

The top-level controller is used to provide a human-computer interaction control interface, receive control instructions from the upper-level system, issue control instructions to the charging and discharging components and input contactor K1, and issue control instructions to the bottom-level controller to receive, process, and send various instructions to control charging. The device completes the work according to the predetermined process, and has an interlock function to prevent misoperation. The bottom controller is used to collect the voltage and current data to complete the closed-loop operation according to the received control instructions, realize the on-off control of the IGBT in the three-level inverter component, and perform software and hardware protection in the event of a fault.

As shown in Figure 5, the online charging control method uses the maximum value of the two output currents as the feedback current to participate in the PI operation to obtain the phase shift angle of the left and right bridge arms of the three-level inverter component 2, and the charging device maintains a constant current by adjusting the phase shift angle. Output, use the maximum value of the two output voltages to participate in the hysteresis judgment to prevent the super capacitor from overvoltage. When the supercapacitor voltage is less than the threshold 1, the PI regulator is enabled, and the charging device outputs two constant currents to charge the supercapacitor; when the supercapacitor voltage is greater than or equal to the threshold 2, the PI regulator is disabled, and the charging device stops charging, where the threshold 2 greater than threshold 1.

Claims (8)

1. The utility model provides a medium voltage direct current input dual output three-level phase-shift full-bridge charging device which characterized in that: the high-frequency-conversion-efficiency energy-saving power supply system comprises an input loop (1), a three-level inverter assembly (2), a three-winding intermediate frequency transformer (3), a rectifier assembly (4) and an output loop (5), wherein the input loop (1) obtains power from a medium-voltage direct current power grid and conveys the power to the three-level inverter assembly (2), the three-level inverter assembly (2) converts direct current into medium-frequency alternating current and conveys the medium-frequency alternating current to the three-winding intermediate frequency transformer (3), the medium-frequency alternating current is subjected to voltage reduction by the three-winding intermediate frequency transformer (3) and then is conveyed to the rectifier assembly (4) in two ways, the rectifier assembly (4) converts the two ways of medium-frequency alternating current into two ways of direct current and conveys the two ways of direct current to the output loop (5), and the output loop (5) charges two ways of super capacitors after filtering the two ways of direct current;

the input circuit (1) comprises an input fuse F1, an input fuse F2, an input contactor K1, an input smoothing reactor L1, an input smoothing reactor L2, an input diode D1, a supporting capacitor C1, a supporting capacitor C2, a voltage equalizing resistor Rj1, a voltage equalizing resistor Rj2 and a charging and discharging component consisting of a charging switch Kc1, a charging resistor Rc1, a charging reactor Lc1, a charging switch Kc2, a charging resistor Rc2, a charging reactor Lc2, a discharging switch Kd and a discharging resistor Rd; the input contactor K1 is of a mechanical holding type, and the contact is controlled not to be opened when power is off;

the online charging control method of the medium-voltage direct-current input double-output three-level phase-shifted full-bridge charging device comprises the steps of taking the maximum value of two paths of output currents as feedback currents to participate in PI operation to obtain the phase shift angles of left and right bridge arms of a three-level inversion assembly (2), enabling the charging device to keep constant-current output by adjusting the phase shift angles, and taking the maximum value of two paths of output voltages to participate in hysteresis loop judgment to prevent overvoltage of a super capacitor; when the voltage of the super capacitor is smaller than a threshold value 1, enabling the PI regulator, and outputting two paths of constant current to charge the super capacitor by the charging device; and when the voltage of the super capacitor is greater than or equal to a threshold value 2, the PI regulator is forbidden, and the charging device stops charging, wherein the threshold value 2 is greater than a threshold value 1.

2. The medium-voltage direct-current input dual-output three-level phase-shifted full-bridge charging device according to claim 1, wherein: the three-level inverter is characterized by further comprising a control system (7), wherein the control system (7) is in bidirectional communication with the input circuit (1), the three-level inverter component (2), the three-winding intermediate frequency transformer (3), the rectifying component (4) and the output circuit (5) respectively.

3. The medium-voltage direct-current input dual-output three-level phase-shifted full-bridge charging device according to claim 1, wherein: the three-level inverter is characterized by further comprising a closed circulating cooling water path (6) for taking away heat generated in the operation process of the input circuit (1), the three-level inverter component (2), the three-winding intermediate frequency transformer (3), the rectifier component (4) and the output circuit (5).

4. The medium-voltage direct-current input dual-output three-level phase-shifted full-bridge charging device according to claim 1, wherein: the three-level inverter component (2) comprises an IGBT-T1, an IGBT-T2, an IGBT-T3, an IGBT-T4, an IGBT-T5, an IGBT-T6, an IGBT-T7, an IGBT-T8, a clamping diode Dc1, a clamping diode Dc2, a clamping diode Dc3, a clamping diode Dc4, an inner tube protection resistor Rj3, an inner tube protection resistor Rj4, an absorption capacitor Cs1 and an absorption capacitor Cs 2.

5. The medium-voltage direct-current input dual-output three-level phase-shifted full-bridge charging device according to claim 1, wherein: the three-winding intermediate frequency transformer (3) comprises 1 primary winding and 2 secondary windings; the rectifying component (4) comprises a rectifying diode Dr1, a rectifying diode Dr2, a rectifying diode Dr3, a rectifying diode Dr4 and a resistance-capacitance absorption circuit.

6. The medium-voltage direct-current input dual-output three-level phase-shifted full-bridge charging device according to claim 1, wherein: the output loop (5) comprises an output filter reactor L3, an output filter reactor L4, an output diode D2, an output fuse F3 and an output fuse F4.

7. The medium voltage dc input dual-output three-level phase-shifted full-bridge charging device according to claim 2, wherein: the control system (7) comprises a top layer controller and a bottom layer controller, and the top layer controller and the bottom layer controller are connected through a CAN bus and a hard wire; the top layer controller is used for providing a man-machine interaction control interface, receiving a superior system control instruction, sending a control instruction to the charging and discharging assembly and the input contactor K1, and sending a control instruction to the bottom layer controller; and the bottom layer controller is used for collecting voltage and current data to complete closed-loop operation according to the received control instruction, and realizing on-off control of the IGBT in the three-level inverter assembly.

8. The medium-voltage direct-current input dual-output three-level phase-shifted full-bridge charging device according to claim 3, wherein: the closed circulating cooling water channel (6) comprises a main water inlet pipe (8), a main water drainage pipe (9), an input diode D1 branch (10), a three-level inverter component branch (19), a three-level inverter component water cooling plate (15), a three-winding intermediate frequency transformer branch (16), a rectifier component water cooling plate (14), a rectifier component branch (18), an output filter reactor branch (13), an output diode D2 branch (17), an output diode D2 water cooling plate (12) and a water-air heat exchanger branch (13), wherein a water inlet of the input diode D1 branch (10), a water inlet of the three-level inverter component branch (19), a water inlet of the rectifier component branch (18), a water inlet of the output filter reactor branch (13), a water inlet of the output diode D2 branch (17), a water inlet of the three-winding intermediate frequency transformer branch (16) and a water inlet of the water-air heat exchanger branch (13) are all connected with the main water inlet pipe (8), the water outlet of the input diode D1 branch (10), the water outlet of the three-level inverter component branch (19), the water outlet of the rectifier component branch (18), the water outlet of the output filter reactor branch (13), the water outlet of the output diode D2 branch (17), the water outlet of the three-winding intermediate frequency transformer branch (16) and the water outlet of the water-air heat exchanger branch (13) are all connected with a main drainage pipe (9), the three-level inverter component water cooling plate (15) is connected with the three-level inverter component branch (19), the rectifier component water cooling plate (14) is connected with the rectifier component branch (18), and the output diode D2 water cooling plate (12) is connected with the output diode D2 branch (17).

Images